#1 Tire Sealant for Tubeless and Tubeless Ready Mountain Bike (MTB) Tires! TireJect MTB will permanently FIX an existing flat tire and PREVENTS flat tires. TireJect is the only MTB tire sealant that contains active sealing fibers that are uniformly distributed within the sealant for superior sealing capabilities. The aramid sealing fibers and recycled rubber tire particles clot together to form a super strong aramid fiber plug while the liquid rubber bonds to the tire for a permanent seal.